Hydraulic system for pressurization of gas with reduction of dead volume

Patent metadata

Field	Value
Publication number	US-2016153447-A1
Application number	US-201414904598-A
Country	US
Kind code	A1
Filing date	Jul 14, 2014
Priority date	Jul 12, 2013
Publication date	Jun 2, 2016
Grant date	—

Abstract

A hydraulic system is provided to reduce a dead volume when pressurizing gas. The system includes a gas source, a gas output, a pressure vessel coupled to the gas source and the gas output, a hydraulic system that forces hydraulic fluid into the pressure vessel from the gas source to compress gas, and an overflow tank that receives overflow of hydraulic fluid once all gas has been expelled from the pressure vessel via the gas output.

First claim

What is claimed is:

1 . A system for compressing gas, the system comprising:
a source of gas; a gas output location; first and second pressure vessels; first and second gas input lines for directing gas from the source of gas respectively to the first and second pressure vessels; first and second gas output lines for directing gas respectively from the first and second pressure vessels to the gas output location; a hydraulic system for moving hydraulic fluid back and forth between the first and second pressure vessels to compress gas in the first and second pressure vessels in an alternating manner, wherein gas is pressurized in the first pressure vessel by directing a first charge of gas from the source of gas into the first pressure vessel through the first gas input line and moving hydraulic fluid from the second pressure tank to the first pressure tank to compress the first charge of gas within the first pressure vessel, wherein gas is pressurized in the second pressure vessel by directing a second charge of gas from the source of gas into the second pressure vessel through the second gas input line and moving hydraulic fluid from both of the first pressure tank and the fluid overflow tank to the second pressure tank to compress the second charge of gas within the second pressure vessel; and an overflow arrangement for allowing all gas to be expelled from the first and second pressure vessels during pressurization of the gas, wherein at least some hydraulic fluid flows into the overflow arrangement when all of the first charge of gas has been forced from the first pressure vessel; and wherein at least some hydraulic fluid flows into the overflow arrangement when all of the second charge of gas has been forced from the second pressure vessel.

2 . The system of claim 1 , wherein the overflow arrangement empties to the second pressure vessel each time after gas compression is complete at the first pressure vessel, and the overflow arrangement empties to the first pressure vessel each time gas compression is completed at the second pressure vessel.

3 . The system of claim 1 , wherein the overflow arrangement includes an overflow tank having a first branch and a second branch.

4 . The system of claim 3 , wherein hydraulic fluid from the first pressure vessel flows into the first branch and hydraulic fluid from the second pressure vessel flows into the second branch.

5 . The system of claim 1 , wherein the overflow arrangement includes an overflow tank that includes at least one sensor, wherein when the hydraulic fluid flows into the fluid overflow tank and reaches the at least one sensor, the hydraulic fluid in the fluid overflow tank is forced out of the fluid overflow tank and into at least one of the first and second pressure vessels.

6 . The system of claim 5 , wherein the system includes a control valve which is in communication with the at least one sensor.

7 . The system of claim 1 , wherein the overflow arrangement includes an overflow tank that includes a first sensor and a second sensor wherein when the hydraulic fluid flows into the fluid overflow tank and reaches the first sensor, the hydraulic fluid in the fluid overflow tank is forced out of the fluid overflow tank and into at least one of the first and second pressure vessels, and wherein when the hydraulic fluid reaches the second sensor, the hydraulic fluid cannot flow out of the fluid overflow tank.

8 . The system of claim 7 , wherein the system includes a first control valve which is in communication with the first sensor and a second control valve which is in communication with the second sensor.

9 . The system of claim 1 , wherein the system includes a spool valve which controls a direction of flow of the hydraulic fluid.

10 . The system of claim 1 , wherein the fluid overflow tank includes two independent fluid overflow tanks.

11 . The system of claim 1 , wherein the system is capable of outputting a maximum gas pressure less than or equal to 4500 psi.

12 . The system of claim 1 , wherein the system is capable of outputting a maximum gas pressure less than or equal to 4000 psi.

13 . The system of claim 1 , wherein the first and second pressure vessels each have a volume less than 10 liters.

14 . The system of claim 1 , wherein the hydraulic system includes a hydraulic flow line that fluidly connects the first and second pressure vessels together and a hydraulic pump for moving hydraulic fluid through the hydraulic flow line between the first and second pressure vessels.

15 . The system of claim 1 , wherein the overflow arrangement includes an overflow tank that has a fluid output line that is coupled to a bottom of the first pressure vessel.

16 . The system of claim 1 , wherein a cooler is positioned along the hydraulic flow for cooling the hydraulic fluid.

17 . A method for compressing gas, the method comprising:
directing a charge of gas to a pressure vessel; moving hydraulic fluid into the pressure vessel to compress the charge of gas; forcing all of the compressed gas out of the pressure vessel to a charge tank; and allowing a portion of the hydraulic fluid to flow into an overflow tank.

18 . The method of claim 17 , wherein the charge of gas is compressed with a compression ratio of greater than 200 to 1.

19 . The method of claim 17 , wherein the charge of gas is compressed to 1500 psi.

20 . The method of claim 17 , wherein the charge of gas is hydrogen.

21 . The method of claim 17 , wherein the tank is a compressed gas tank positioned within a vehicle.

22 . The method of claim 17 , wherein the charge of gas is a natural as.

23 . A method for compressing gas, the method comprising:
directing a first charge of natural gas to a first pressure vessel; directing hydraulic fluid from a second pressure vessel to the first pressure vessel to compress the first charge of natural gas; forcing all of the compressed gas out of the first pressure vessel; allowing a portion of the hydraulic fluid in the first pressure vessel to leave the first pressure vessel and flow into an overflow tank; directing a second charge of natural gas to the second pressure vessel; and when the fluid in the overflow tank reaches a predetermined level, allowing at east a portion of the fluid in the overflow tank to flow into the second pressure vessel.

24 . A system comprising:
a gas source; a gas output; a pressure vessel coupled to the gas source and the gas output; a hydraulic system that forces hydraulic fluid into the pressure vessel from the gas source to compress gas; and an overflow tank that receives overflow of hydraulic fluid once all gas has been expelled from the pressure vessel via the gas output.

Assignees

• Eaton Corp

Inventors

• Yuan Qinghui

Classifications

• F17C2265/065

  for refuelling vehicle fuel tanks · CPC title

• F17C2223/0123

  gaseous, e.g. CNG, GNC · CPC title

• F17C5/06

  for filling with compressed gases · CPC title

• F17C2227/046

  by even emptying or filling · CPC title

• F17C2270/0139

  Fuel stations · CPC title